radicale/radicale/storage.py
2017-05-27 17:28:07 +02:00

832 lines
29 KiB
Python

# This file is part of Radicale Server - Calendar Server
# Copyright © 2014 Jean-Marc Martins
# Copyright © 2012-2017 Guillaume Ayoub
#
# This library is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Radicale. If not, see <http://www.gnu.org/licenses/>.
"""
Storage backends.
This module loads the storage backend, according to the storage configuration.
Default storage uses one folder per collection and one file per collection
entry.
"""
import contextlib
import datetime
import errno
import json
import os
import posixpath
import shlex
import stat
import subprocess
import threading
import time
from contextlib import contextmanager
from hashlib import md5
from importlib import import_module
from itertools import groupby
from random import getrandbits
from tempfile import NamedTemporaryFile, TemporaryDirectory
import vobject
if os.name == "nt":
import ctypes
import ctypes.wintypes
import msvcrt
LOCKFILE_EXCLUSIVE_LOCK = 2
if ctypes.sizeof(ctypes.c_void_p) == 4:
ULONG_PTR = ctypes.c_uint32
else:
ULONG_PTR = ctypes.c_uint64
class Overlapped(ctypes.Structure):
_fields_ = [
("internal", ULONG_PTR),
("internal_high", ULONG_PTR),
("offset", ctypes.wintypes.DWORD),
("offset_high", ctypes.wintypes.DWORD),
("h_event", ctypes.wintypes.HANDLE)]
lock_file_ex = ctypes.windll.kernel32.LockFileEx
lock_file_ex.argtypes = [
ctypes.wintypes.HANDLE,
ctypes.wintypes.DWORD,
ctypes.wintypes.DWORD,
ctypes.wintypes.DWORD,
ctypes.wintypes.DWORD,
ctypes.POINTER(Overlapped)]
lock_file_ex.restype = ctypes.wintypes.BOOL
unlock_file_ex = ctypes.windll.kernel32.UnlockFileEx
unlock_file_ex.argtypes = [
ctypes.wintypes.HANDLE,
ctypes.wintypes.DWORD,
ctypes.wintypes.DWORD,
ctypes.wintypes.DWORD,
ctypes.POINTER(Overlapped)]
unlock_file_ex.restype = ctypes.wintypes.BOOL
elif os.name == "posix":
import fcntl
def load(configuration, logger):
"""Load the storage manager chosen in configuration."""
storage_type = configuration.get("storage", "type")
if storage_type == "multifilesystem":
collection_class = Collection
else:
collection_class = import_module(storage_type).Collection
class CollectionCopy(collection_class):
"""Collection copy, avoids overriding the original class attributes."""
CollectionCopy.configuration = configuration
CollectionCopy.logger = logger
return CollectionCopy
def get_etag(text):
"""Etag from collection or item.
Encoded as quoted-string (see RFC 2616).
"""
etag = md5()
etag.update(text.encode("utf-8"))
return '"%s"' % etag.hexdigest()
def get_uid(item):
"""UID value of an item if defined."""
return hasattr(item, "uid") and item.uid.value
def sanitize_path(path):
"""Make path absolute with leading slash to prevent access to other data.
Preserve a potential trailing slash.
"""
trailing_slash = "/" if path.endswith("/") else ""
path = posixpath.normpath(path)
new_path = "/"
for part in path.split("/"):
if not is_safe_path_component(part):
continue
new_path = posixpath.join(new_path, part)
trailing_slash = "" if new_path.endswith("/") else trailing_slash
return new_path + trailing_slash
def is_safe_path_component(path):
"""Check if path is a single component of a path.
Check that the path is safe to join too.
"""
return path and "/" not in path and path not in (".", "..")
def is_safe_filesystem_path_component(path):
"""Check if path is a single component of a local and posix filesystem
path.
Check that the path is safe to join too.
"""
return (
path and not os.path.splitdrive(path)[0] and
not os.path.split(path)[0] and path not in (os.curdir, os.pardir) and
not path.startswith(".") and not path.endswith("~") and
is_safe_path_component(path))
def path_to_filesystem(root, *paths):
"""Convert path to a local filesystem path relative to base_folder.
`root` must be a secure filesystem path, it will be prepend to the path.
Conversion of `paths` is done in a secure manner, or raises ``ValueError``.
"""
paths = [sanitize_path(path).strip("/") for path in paths]
safe_path = root
for path in paths:
if not path:
continue
for part in path.split("/"):
if not is_safe_filesystem_path_component(part):
raise UnsafePathError(part)
safe_path_parent = safe_path
safe_path = os.path.join(safe_path, part)
# Check for conflicting files (e.g. case-insensitive file systems
# or short names on Windows file systems)
if os.path.lexists(safe_path):
if part not in os.listdir(safe_path_parent):
raise CollidingPathError(part)
return safe_path
class UnsafePathError(ValueError):
def __init__(self, path):
message = "Can't translate name safely to filesystem: %s" % path
super().__init__(message)
class CollidingPathError(ValueError):
def __init__(self, path):
message = "File name collision: %s" % path
super().__init__(message)
class ComponentExistsError(ValueError):
def __init__(self, path):
message = "Component already exists: %s" % path
super().__init__(message)
class ComponentNotFoundError(ValueError):
def __init__(self, path):
message = "Component doesn't exist: %s" % path
super().__init__(message)
class Item:
def __init__(self, collection, item, href, last_modified=None):
self.collection = collection
self.item = item
self.href = href
self.last_modified = last_modified
def __getattr__(self, attr):
return getattr(self.item, attr)
@property
def etag(self):
"""Encoded as quoted-string (see RFC 2616)."""
return get_etag(self.serialize())
class BaseCollection:
# Overriden on copy by the "load" function
configuration = None
logger = None
def __init__(self, path, principal=False):
"""Initialize the collection.
``path`` must be the normalized relative path of the collection, using
the slash as the folder delimiter, with no leading nor trailing slash.
"""
raise NotImplementedError
@classmethod
def discover(cls, path, depth="0"):
"""Discover a list of collections under the given ``path``.
If ``depth`` is "0", only the actual object under ``path`` is
returned.
If ``depth`` is anything but "0", it is considered as "1" and direct
children are included in the result.
The ``path`` is relative.
The root collection "/" must always exist.
"""
raise NotImplementedError
@classmethod
def move(cls, item, to_collection, to_href):
"""Move an object.
``item`` is the item to move.
``to_collection`` is the target collection.
``to_href`` is the target name in ``to_collection``. An item with the
same name might already exist.
"""
if item.collection.path == to_collection.path and item.href == to_href:
return
to_collection.upload(to_href, item.item)
item.collection.delete(item.href)
@property
def etag(self):
"""Encoded as quoted-string (see RFC 2616)."""
return get_etag(self.serialize())
@classmethod
def create_collection(cls, href, collection=None, props=None):
"""Create a collection.
If the collection already exists and neither ``collection`` nor
``props`` are set, this method shouldn't do anything. Otherwise the
existing collection must be replaced.
``collection`` is a list of vobject components.
``props`` are metadata values for the collection.
``props["tag"]`` is the type of collection (VCALENDAR or
VADDRESSBOOK). If the key ``tag`` is missing, it is guessed from the
collection.
"""
raise NotImplementedError
def list(self):
"""List collection items."""
raise NotImplementedError
def get(self, href):
"""Fetch a single item."""
raise NotImplementedError
def get_multi(self, hrefs):
"""Fetch multiple items. Duplicate hrefs must be ignored.
Functionally similar to ``get``, but might bring performance benefits
on some storages when used cleverly.
"""
for href in set(hrefs):
yield self.get(href)
def pre_filtered_list(self, filters):
"""List collection items with optional pre filtering.
This could largely improve performance of reports depending on
the filters and this implementation.
This returns all event by default
"""
return [self.get(href) for href in self.list()]
def has(self, href):
"""Check if an item exists by its href.
Functionally similar to ``get``, but might bring performance benefits
on some storages when used cleverly.
"""
return self.get(href) is not None
def upload(self, href, vobject_item):
"""Upload a new or replace an existing item."""
raise NotImplementedError
def delete(self, href=None):
"""Delete an item.
When ``href`` is ``None``, delete the collection.
"""
raise NotImplementedError
def get_meta(self, key):
"""Get metadata value for collection."""
raise NotImplementedError
def set_meta(self, props):
"""Set metadata values for collection."""
raise NotImplementedError
@property
def last_modified(self):
"""Get the HTTP-datetime of when the collection was modified."""
raise NotImplementedError
def serialize(self):
"""Get the unicode string representing the whole collection."""
raise NotImplementedError
@classmethod
@contextmanager
def acquire_lock(cls, mode, user=None):
"""Set a context manager to lock the whole storage.
``mode`` must either be "r" for shared access or "w" for exclusive
access.
``user`` is the name of the logged in user or empty.
"""
raise NotImplementedError
class Collection(BaseCollection):
"""Collection stored in several files per calendar."""
def __init__(self, path, principal=False, folder=None):
if not folder:
folder = self._get_collection_root_folder()
# Path should already be sanitized
self.path = sanitize_path(path).strip("/")
self.encoding = self.configuration.get("encoding", "stock")
self._filesystem_path = path_to_filesystem(folder, self.path)
self._props_path = os.path.join(
self._filesystem_path, ".Radicale.props")
split_path = self.path.split("/")
self.owner = split_path[0] if len(split_path) > 1 else None
self.is_principal = principal
@classmethod
def _get_collection_root_folder(cls):
filesystem_folder = os.path.expanduser(
cls.configuration.get("storage", "filesystem_folder"))
return os.path.join(filesystem_folder, "collection-root")
@contextmanager
def _atomic_write(self, path, mode="w", newline=None):
directory = os.path.dirname(path)
tmp = NamedTemporaryFile(
mode=mode, dir=directory, encoding=self.encoding,
delete=False, prefix=".Radicale.tmp-", newline=newline)
try:
yield tmp
self._fsync(tmp.fileno())
tmp.close()
os.replace(tmp.name, path)
except:
tmp.close()
os.remove(tmp.name)
raise
self._sync_directory(directory)
@staticmethod
def _find_available_file_name(exists_fn):
# Prevent infinite loop
for _ in range(10000):
file_name = hex(getrandbits(32))[2:]
if not exists_fn(file_name):
return file_name
raise FileExistsError(errno.EEXIST, "No usable file name found")
@classmethod
def _fsync(cls, fd):
if cls.configuration.getboolean("storage", "filesystem_fsync"):
if os.name == "posix" and hasattr(fcntl, "F_FULLFSYNC"):
fcntl.fcntl(fd, fcntl.F_FULLFSYNC)
else:
os.fsync(fd)
@classmethod
def _sync_directory(cls, path):
"""Sync directory to disk.
This only works on POSIX and does nothing on other systems.
"""
if not cls.configuration.getboolean("storage", "filesystem_fsync"):
return
if os.name == "posix":
fd = os.open(path, 0)
try:
cls._fsync(fd)
finally:
os.close(fd)
@classmethod
def _makedirs_synced(cls, filesystem_path):
"""Recursively create a directory and its parents in a sync'ed way.
This method acts silently when the folder already exists.
"""
if os.path.isdir(filesystem_path):
return
parent_filesystem_path = os.path.dirname(filesystem_path)
# Prevent infinite loop
if filesystem_path != parent_filesystem_path:
# Create parent dirs recursively
cls._makedirs_synced(parent_filesystem_path)
# Possible race!
os.makedirs(filesystem_path, exist_ok=True)
cls._sync_directory(parent_filesystem_path)
@classmethod
def discover(cls, path, depth="0"):
if path is None:
# Wrong URL
return
# Path should already be sanitized
sane_path = sanitize_path(path).strip("/")
attributes = sane_path.split("/")
if not attributes[0]:
attributes.pop()
folder = cls._get_collection_root_folder()
# Create the root collection
cls._makedirs_synced(folder)
try:
filesystem_path = path_to_filesystem(folder, sane_path)
except ValueError as e:
# Path is unsafe
cls.logger.info(e)
return
# Check if the path exists and if it leads to a collection or an item
if not os.path.isdir(filesystem_path):
if attributes and os.path.isfile(filesystem_path):
href = attributes.pop()
else:
return
else:
href = None
path = "/".join(attributes)
principal = len(attributes) == 1
collection = cls(path, principal)
if href:
yield collection.get(href)
return
yield collection
if depth == "0":
return
for item in collection.list():
yield collection.get(item)
for href in os.listdir(filesystem_path):
if not is_safe_filesystem_path_component(href):
if not href.startswith(".Radicale"):
cls.logger.debug("Skipping collection: %s", href)
continue
child_filesystem_path = path_to_filesystem(filesystem_path, href)
if os.path.isdir(child_filesystem_path):
child_path = posixpath.join(path, href)
child_principal = len(attributes) == 0
yield cls(child_path, child_principal)
@classmethod
def create_collection(cls, href, collection=None, props=None):
folder = cls._get_collection_root_folder()
# Path should already be sanitized
sane_path = sanitize_path(href).strip("/")
attributes = sane_path.split("/")
if not attributes[0]:
attributes.pop()
principal = len(attributes) == 1
filesystem_path = path_to_filesystem(folder, sane_path)
if not props:
props = {}
if not props.get("tag") and collection:
props["tag"] = collection[0].name
if not props:
cls._makedirs_synced(filesystem_path)
return cls(sane_path, principal=principal)
parent_dir = os.path.dirname(filesystem_path)
cls._makedirs_synced(parent_dir)
# Create a temporary directory with an unsafe name
with TemporaryDirectory(
prefix=".Radicale.tmp-", dir=parent_dir) as tmp_dir:
# The temporary directory itself can't be renamed
tmp_filesystem_path = os.path.join(tmp_dir, "collection")
os.makedirs(tmp_filesystem_path)
self = cls("/", principal=principal, folder=tmp_filesystem_path)
self.set_meta(props)
if collection:
if props.get("tag") == "VCALENDAR":
collection, = collection
items = []
for content in ("vevent", "vtodo", "vjournal"):
items.extend(
getattr(collection, "%s_list" % content, []))
items_by_uid = groupby(sorted(items, key=get_uid), get_uid)
vobject_items = {}
for uid, items in items_by_uid:
new_collection = vobject.iCalendar()
for item in items:
new_collection.add(item)
href = self._find_available_file_name(
vobject_items.get)
vobject_items[href] = new_collection
self.upload_all_nonatomic(vobject_items)
elif props.get("tag") == "VCARD":
vobject_items = {}
for card in collection:
href = self._find_available_file_name(
vobject_items.get)
vobject_items[href] = card
self.upload_all_nonatomic(vobject_items)
# This operation is not atomic on the filesystem level but it's
# very unlikely that one rename operations succeeds while the
# other fails or that only one gets written to disk.
if os.path.exists(filesystem_path):
os.rename(filesystem_path, os.path.join(tmp_dir, "delete"))
os.rename(tmp_filesystem_path, filesystem_path)
cls._sync_directory(parent_dir)
return cls(sane_path, principal=principal)
def upload_all_nonatomic(self, vobject_items):
"""Upload a new set of items.
This takes a mapping of href and vobject items and
uploads them nonatomic and without existence checks.
"""
with contextlib.ExitStack() as stack:
fs = []
for href, item in vobject_items.items():
if not is_safe_filesystem_path_component(href):
raise UnsafePathError(href)
path = path_to_filesystem(self._filesystem_path, href)
fs.append(stack.enter_context(
open(path, "w", encoding=self.encoding, newline="")))
fs[-1].write(item.serialize())
# sync everything at once because it's slightly faster.
for f in fs:
self._fsync(f.fileno())
self._sync_directory(self._filesystem_path)
@classmethod
def move(cls, item, to_collection, to_href):
if not is_safe_filesystem_path_component(to_href):
raise UnsafePathError(to_href)
os.replace(
path_to_filesystem(item.collection._filesystem_path, item.href),
path_to_filesystem(to_collection._filesystem_path, to_href))
cls._sync_directory(to_collection._filesystem_path)
if item.collection._filesystem_path != to_collection._filesystem_path:
cls._sync_directory(item.collection._filesystem_path)
def list(self):
for href in os.listdir(self._filesystem_path):
if not is_safe_filesystem_path_component(href):
if not href.startswith(".Radicale"):
self.logger.debug("Skipping component: %s", href)
continue
path = os.path.join(self._filesystem_path, href)
if os.path.isfile(path):
yield href
def get(self, href):
if not href:
return None
if not is_safe_filesystem_path_component(href):
self.logger.debug(
"Can't translate name safely to filesystem: %s", href)
return None
path = path_to_filesystem(self._filesystem_path, href)
if not os.path.isfile(path):
return None
with open(path, encoding=self.encoding, newline="") as f:
text = f.read()
last_modified = time.strftime(
"%a, %d %b %Y %H:%M:%S GMT",
time.gmtime(os.path.getmtime(path)))
try:
item = vobject.readOne(text)
except Exception:
self.logger.error("Failed to parse component: %s", href)
raise
return Item(self, item, href, last_modified)
def upload(self, href, vobject_item):
if not is_safe_filesystem_path_component(href):
raise UnsafePathError(href)
path = path_to_filesystem(self._filesystem_path, href)
item = Item(self, vobject_item, href)
with self._atomic_write(path, newline="") as fd:
fd.write(item.serialize())
return item
def delete(self, href=None):
if href is None:
# Delete the collection
parent_dir = os.path.dirname(self._filesystem_path)
try:
os.rmdir(self._filesystem_path)
except OSError:
with TemporaryDirectory(
prefix=".Radicale.tmp-", dir=parent_dir) as tmp:
os.rename(self._filesystem_path, os.path.join(
tmp, os.path.basename(self._filesystem_path)))
self._sync_directory(parent_dir)
else:
self._sync_directory(parent_dir)
else:
# Delete an item
if not is_safe_filesystem_path_component(href):
raise UnsafePathError(href)
path = path_to_filesystem(self._filesystem_path, href)
if not os.path.isfile(path):
raise ComponentNotFoundError(href)
os.remove(path)
self._sync_directory(os.path.dirname(path))
def get_meta(self, key=None):
if os.path.exists(self._props_path):
with open(self._props_path, encoding=self.encoding) as f:
meta = json.load(f)
return meta.get(key) if key else meta
def set_meta(self, props):
if os.path.exists(self._props_path):
with open(self._props_path, encoding=self.encoding) as f:
old_props = json.load(f)
old_props.update(props)
props = old_props
props = {key: value for key, value in props.items() if value}
with self._atomic_write(self._props_path, "w+") as f:
json.dump(props, f)
@property
def last_modified(self):
relevant_files = [self._filesystem_path] + [
path_to_filesystem(self._filesystem_path, href)
for href in self.list()]
if os.path.exists(self._props_path):
relevant_files.append(self._props_path)
last = max(map(os.path.getmtime, relevant_files))
return time.strftime("%a, %d %b %Y %H:%M:%S GMT", time.gmtime(last))
def serialize(self):
items = []
time_begin = datetime.datetime.now()
for href in self.list():
items.append(self.get(href).item)
time_end = datetime.datetime.now()
self.logger.info(
"Collection read %d items in %s sec from %s", len(items),
(time_end - time_begin).total_seconds(), self._filesystem_path)
if self.get_meta("tag") == "VCALENDAR":
collection = vobject.iCalendar()
for item in items:
for content in ("vevent", "vtodo", "vjournal"):
if content in item.contents:
for item_part in getattr(item, "%s_list" % content):
collection.add(item_part)
break
return collection.serialize()
elif self.get_meta("tag") == "VADDRESSBOOK":
return "".join([item.serialize() for item in items])
return ""
_lock = threading.Lock()
_waiters = []
_lock_file = None
_lock_file_locked = False
_readers = 0
_writer = False
@classmethod
@contextmanager
def acquire_lock(cls, mode, user=None):
def condition():
if mode == "r":
return not cls._writer
else:
return not cls._writer and cls._readers == 0
folder = os.path.expanduser(cls.configuration.get(
"storage", "filesystem_folder"))
# Use a primitive lock which only works within one process as a
# precondition for inter-process file-based locking
with cls._lock:
if cls._waiters or not condition():
# Use FIFO for access requests
waiter = threading.Condition(lock=cls._lock)
cls._waiters.append(waiter)
while True:
waiter.wait()
if condition():
break
cls._waiters.pop(0)
if mode == "r":
cls._readers += 1
# Notify additional potential readers
if cls._waiters:
cls._waiters[0].notify()
else:
cls._writer = True
if not cls._lock_file:
cls._makedirs_synced(folder)
lock_path = os.path.join(folder, ".Radicale.lock")
cls._lock_file = open(lock_path, "w+")
# Set access rights to a necessary minimum to prevent locking
# by arbitrary users
try:
os.chmod(lock_path, stat.S_IWUSR | stat.S_IRUSR)
except OSError:
cls.logger.debug("Failed to set permissions on lock file")
if not cls._lock_file_locked:
if os.name == "nt":
handle = msvcrt.get_osfhandle(cls._lock_file.fileno())
flags = LOCKFILE_EXCLUSIVE_LOCK if mode == "w" else 0
overlapped = Overlapped()
if not lock_file_ex(handle, flags, 0, 1, 0, overlapped):
cls.logger.debug("Locking not supported")
elif os.name == "posix":
_cmd = fcntl.LOCK_EX if mode == "w" else fcntl.LOCK_SH
try:
fcntl.flock(cls._lock_file.fileno(), _cmd)
except OSError:
cls.logger.debug("Locking not supported")
cls._lock_file_locked = True
try:
yield
# execute hook
hook = cls.configuration.get("storage", "hook")
if mode == "w" and hook:
cls.logger.debug("Running hook")
subprocess.check_call(
hook % {"user": shlex.quote(user or "Anonymous")},
shell=True, cwd=folder)
finally:
with cls._lock:
if mode == "r":
cls._readers -= 1
else:
cls._writer = False
if cls._readers == 0:
if os.name == "nt":
handle = msvcrt.get_osfhandle(cls._lock_file.fileno())
overlapped = Overlapped()
if not unlock_file_ex(handle, 0, 1, 0, overlapped):
cls.logger.debug("Unlocking not supported")
elif os.name == "posix":
try:
fcntl.flock(cls._lock_file.fileno(), fcntl.LOCK_UN)
except OSError:
cls.logger.debug("Unlocking not supported")
cls._lock_file_locked = False
if cls._waiters:
cls._waiters[0].notify()
if (cls.configuration.getboolean(
"storage", "filesystem_close_lock_file") and
cls._readers == 0 and not cls._waiters):
cls._lock_file.close()
cls._lock_file = None